CN115998497A

CN115998497A - Support frame

Info

Publication number: CN115998497A
Application number: CN202211304219.1A
Authority: CN
Inventors: 托马斯·维勒; 蒂洛·瓦克; 法比安·施密特; 阿希姆·齐普泽
Original assignee: Optermead Medical Devices Co ltd
Current assignee: Optermead Medical Devices Co ltd
Priority date: 2021-10-22
Filing date: 2022-10-24
Publication date: 2023-04-25
Also published as: EP4169489A1; BR102022021415A2; DE102021127510A1; US20230131256A1; JP2023063278A; AU2022259702A1

Abstract

The invention relates to a stent for transluminal implantation in a hollow organ, in particular in a blood vessel, ureter, esophagus, colon, duodenum, airway or bile duct, having an at least substantially tubular body which extends in a longitudinal direction and which can be converted from a compressed state with a first cross-sectional diameter into an expanded state with an enlarged second cross-sectional diameter, wherein the stent comprises a stent body made of a biostable material, the stent body comprises a plurality of, in particular mutually separated, preferably annular stent sections, and the stent has a support structure which connects the stent sections to one another, wherein the support structure is formed from or comprises a bioabsorbable material.

Description

Support frame

Technical Field

The invention relates to a stent for transluminal implantation in a hollow organ, in particular in a blood vessel, ureter, esophagus, colon, duodenum, airway or bile duct, the stent having an at least substantially tubular body which extends in a longitudinal direction. The stent is capable of transitioning from a compressed state having a first cross-sectional diameter to an expanded state having a second cross-sectional diameter that is greater than the first cross-sectional diameter. The stent includes a stent body made of a biostable material.

Background

Stents are used in the treatment of diseased hollow organs, for example, when the hollow organ narrows (stenosis). Another field of application is the treatment of aneurysms.

For treatment, the stent is introduced in a compressed state via an introduction catheter into the hollow organ at the site to be treated, where the stent expands by inflation or self-expansion to a diameter, for example, corresponding to the diameter of a healthy hollow organ, whereby a supporting effect of the hollow organ, in particular of the vessel wall, is achieved. Generally, the stent should provide a high radial vertical force to have a sufficiently large supporting effect, for example for a blood vessel. Furthermore, the stent should be able to accommodate deformations of the hollow organ, such as those due to movements of the patient. Thus, the stent should be flexibly designed to allow for longitudinal deformation.

Furthermore, it is desirable to be able to place the stent in the hollow organ in a simple manner and with a positional accuracy.

Disclosure of Invention

It is therefore an object of the present invention to provide an improved stent which especially takes the above aspects into account.

This object is achieved by a bracket according to claim 1.

The stent according to the invention has the feature that the stent body comprises a plurality, in particular mutually separate, preferably annular stent sections. Furthermore, the stent according to the invention comprises a support structure which connects the annular stent sections to each other, wherein the support structure is formed of or comprises a bioabsorbable material.

The bioabsorbable material will gradually disappear or be absorbed after insertion into the hollow organ, so that after a certain time only the stent body made of the biostable material remains (permanently) in the hollow organ. The invention is therefore based on the following recognition: the stent sections of the stent body can be connected to one another by a support structure made of a bioabsorbable material and can be fixed to one another in this way, for example, in order to simplify the insertion of the stent body into the hollow organ. After dissolution or absorption of the bioabsorbable material, the connection of the stent sections by the support structure is eliminated, whereby, for example, the flexibility of the stent in the longitudinal direction is increased.

Thus, the support structure may be a structure that remains only temporarily in the body, which is advantageous during insertion of the stent into the hollow organ, but is not intended to remain permanently in the hollow organ.

Preferably, the carrier sections are separate from each other. This means: the individual stent sections are not connected to each other by the biostable material of the stent body, but are connected to each other, for example, only by the support structure. After removal of the support structure, a particularly high flexibility in the longitudinal direction is obtained by the separate carrier sections. Furthermore, the carrier sections can be designed as annular, wherein, for example, identical distances can be provided between the annular carrier sections. However, or in addition, any other shape is also possible, such as a beveled and/or irregularly shaped stent section.

In particular, the individual carrier sections are arranged in succession in rows in the longitudinal direction and preferably have a common axis extending in the longitudinal direction.

In principle, the stent has a substantially tubular body. This means that the length of the stent in the longitudinal direction is preferably greater than the cross-sectional diameter of the stent (e.g. at least 2, 5, 10 or 30 times). In the expanded state, the stent may have an empty, continuous lumen/volume within it through which, for example, blood flow may occur. The stent may have a cross-sectional diameter that remains substantially unchanged in the expanded state over its entire length in the longitudinal direction. Alternatively, the cross-sectional diameter may also vary over the length of the stent, e.g. continuously decrease, in order to take account of the decrease in diameter of the hollow organ.

The stent may be a self-expanding stent that automatically transitions from a compressed state to an expanded state without active forces.

Alternatively, the stent may also be non-self-expanding, such as balloon-expandable. The balloon may then be attached inside the stent, wherein the balloon is inflated, expanded under pressure, and upon expansion, the stent is pushed and transformed from a compressed state to an expanded state ("balloon inflation").

The biostable material may be, for example, a nickel titanium alloy (nitinol). Preferably, the stent body is composed of a shape memory ("shape memory") material that occupies a stored shape from a threshold temperature. In addition to the nickel-titanium alloys mentioned, the stent body can also be designed as cobalt-chromium alloy, cobalt-nickel alloy or platinum-chromium alloy, or can comprise these alloys. In addition, other suitable metals and/or metal alloys and/or metal materials are also possible.

The stent may in particular be a "cover stent" which is surrounded by a textile material (Stoffmaterial), for example. Stents may also include stent grafts (Stentgraft). The stent graft is in particular a vascular wall prosthesis which may be used, for example, in the treatment of aneurysms. However, the stents described herein may also be "bare stents", i.e., stents without stent grafts or fabric materials.

In particular, the support structure comprises a plurality of separate parts, i.e. the support structure preferably does not form a respective continuous structure.

The stent body may comprise a plurality of cells defined by boundary elements (e.g., so-called "struts") formed by the stent body. The border element may be formed by cutting the stent body from, in particular, a tubular material, the material being removed, wherein the border element or web is retained. The boundary elements are preferably fixedly connected to one another, in particular, the boundary elements are one-piece. Accordingly, the stent body does not comprise any woven material, for example.

One unit may be connected to one or more other units by one or more connection sections. One unit comprises the entire recess (aussaparum) and the corresponding boundary element of the recess, wherein the connecting section belongs to the boundary element.

Preferably, the cells of the stent body form a convex polygon and in particular have a diamond shape. Alternatively, the cells may also be closed (rund), circular or oval. In particular, the shape of the cell described above can be obtained when the cell is placed on a plane or pressed onto a plane (so-called unfolding). In the case of convex polygons, all internal angles have an angle of 180 ° or less, respectively. Such cells may also be referred to as closed cells. By means of the convex polygon shape and in particular by means of the diamond shape, or also by means of the oval shape, a high vertical bracing force and thus a high bracing effect of the bracket can be obtained.

In particular, most or all of the cells have a convex polygon, diamond, ring, oval and/or circular shape.

Alternatively or additionally, the cells of the stent body may also form a concave polygon. In the case of a concave polygon, at least one interior angle may have an angle >180 °. For example, at least a portion of the boundary element of the respective cell may have a saw tooth shape. The flexibility of the stent may be further increased by such zigzag units or generally by units having a concave polygonal shape. Furthermore, most or all of the cells may have a concave polygonal shape.

Furthermore, it is possible that: most or all of the cells of the stent body may have the same or similar shape. In particular, a similar shape can be considered if the boundary elements of two cells when stacked on top of each other have a maximum offset of no more than 10% or 20% or 30% of the maximum expanded length of the cells in a spatial direction.

Preferably, at least one of the stent sections comprises a row of cells which follow each other in the circumferential direction of the stent and preferably form a closed loop which surrounds the stent in the circumferential direction. The ring has a cross section perpendicular to the longitudinal direction of the stent, preferably closed in the shape of a ring formed by the elements of the ring. By means of such a circumferential ring, which is preferably closed, an optimum radial bracing and supporting action of the stent or of the stent body can be established in the stent sections. In principle, the carrier section can be formed by any unit. In particular, the annular carrier section can have exactly one row or exactly two or three rows of cells connected to one another. By means of two or three rows of units connected to each other, the carrier sections are elongated in the longitudinal direction, but also provide increased vertical support forces.

Advantageous refinements of the invention emerge from the description, the drawing and the dependent claims.

According to a first embodiment, the support structure is designed for holding the carrier sections in a defined relative position to each other. The support structure thus secures the stent sections such that the spacing and/or orientation of the stent sections remains unchanged in the expanded and/or compressed state (at least without the application of a large force from the outside). Maintaining a constant spacing and/or orientation enables improved insertion at a very precisely determined target location. During the absorption of the support structure in the hollow organ, a certain ingrowth of the stent sections (Einwachsen) usually occurs, so that the stent sections remain in their respective positions also without the support structure. However, as already mentioned, the flexibility in the longitudinal direction is preferably increased without a support structure. Alternatively or additionally, in principle the flexibility of the stent body can be improved, whereby the longitudinal extensibility and/or compressibility can be increased and/or the torsion resistance can be improved without a relative reduction in the radial standing forces, i.e. the bracing effect.

In particular, the connection or fixation of the carrier sections by the support structure can also be understood as: relative movement of the support structure and the stent body or stent section is still possible, but accidental disengagement of the support structure and the stent body is prevented.

According to another embodiment, the support structure is at least substantially arranged outside the holder body. When inserted into the hollow organ, the outer side of the stent body rests at least partially against the tissue of the hollow organ. In particular, 50%, more than 80% or more than 95% of the material of the support structure may lie against the outside of the stent body and/or outside the stent body. Preferably, the support structure does not protrude beyond the inner side of the stent body into the hollow lumen in the interior of the stent to avoid damaging blood flow, for example through the hollow lumen.

The components of the support structure are thus in particular arranged such that they press against the wall of the hollow organ or at least are arranged in the region of the wall of the hollow organ, whereby fragments of the support structure are avoided during absorption, for example, from entering the blood stream and being washed away.

According to another embodiment, the support structure comprises a plurality of rails (scheienen) extending at least substantially parallel to the longitudinal direction. The rail may preferably be fixed to the connection section of the unit of the stand body. More preferably, the rails are each designed to be straight and extend, for example, on the outside of the holder body. The force required for introducing the stent into the catheter of the introduction device and/or the force required for removing the stent from the catheter of the introduction device can be reduced by the track. The preparation of the introduction process and the removal of the stent in the hollow organ are thereby simplified. Thus, the track is advantageous when inserting the stent, and then dissolves due to the bioabsorbable material, in the long run, without impeding the flexibility of the stent.

Alternatively or additionally, at least some of the tracks may also have a helical stretch in the longitudinal direction, i.e. at least partially around the axis formed by the stent.

According to another embodiment, the tracks are evenly distributed in the circumferential direction of the tubular body. This means that the track is arranged, as seen in cross section, uniformly, for example along the circumference of the stent body. A track may be provided at least for example every 30 ° or every 45 ° or every 60 ° as seen from the central axis of the holder body.

According to another embodiment, the rails have equal lengths in the longitudinal direction. The length of the track may for example correspond to the length of the stent body. The rail can also be designed shorter than the stent body and for example only have 30%, 40%, 50%, 60% or 70% of the length of the stent body in the longitudinal direction. Alternatively or additionally, at least some of the rails may also be designed to be longer than the stent body.

According to another embodiment, the rail has different positions, seen in the longitudinal direction. Thus, the track may have different starting and/or ending positions in the longitudinal direction. For example, the two tracks may only partially overlap in the longitudinal direction. Also possible are: the rail is spaced from the end of the holder body or the rail protrudes beyond the end of the holder body.

According to a further embodiment, at least one of the rails comprises at least one spring element, which has a higher flexibility than the flexibility of the rail in the region outside the spring element, wherein the spring element is preferably arranged between the two carrier sections. More preferably, the spring element is arranged centrally between the two carrier sections. The flexibility of the support, in particular in the longitudinal direction, is increased by the spring element, since a certain movability of the support sections relative to one another can be achieved by the higher flexibility of the spring element. The spring element preferably comprises a tapered region and/or a zigzag shape and/or a serpentine shape

Wherein a higher flexibility of the spring element is achieved by the tapering region and/or the zigzag shape and/or the meandering shape. In particular, by positioning between the carrier sections, the carrier sections can be moved more flexibly relative to each other as described previously.

According to another embodiment, the support structure is fixed to the bracket body by means of form fit (formschlus) and/or force fit (kraft schlus). In particular, the support structure is fixed to the holder body only by means of a form fit and/or a force fit. Furthermore, it is preferred that the form fit and/or force fit is only performed by the material of the bracket body and the support structure, so that no additional material for e.g. gluing, soldering, welding etc. is needed.

By means of the connection of the support structure and the holder body by means of a form-and/or force-fit, it is achieved that: the biostable material is attached to the bioabsorbable material, although nitinol, for example, is practically impossible to weld to the bioabsorbable material such as zinc. By fixing the support structure to the stent body as described herein, a rational use in hollow organs is still possible.

The connection of the support structure and the holder body by means of form-fitting and/or force-fitting can be carried out in particular as follows: a recess with an undercut (hinterschneidoung) is provided in the holder body, wherein the support structure protrudes into the undercut. For example, the recess with undercut may be shaped in cross section as a substantially trapezoid (for example as an isosceles trapezoid), wherein the trapezoid may be designed to open on its shorter base side, whereby the undercut is formed in the region of the longer base side.

The material of the support structure can be introduced into the region of the recess with undercut and heated there, for example, to briefly liquefy it. The material of the support structure can thereby bear against the holder body in the region of the undercut and in this way form a form fit and possibly also a force fit.

According to a further embodiment, in order to fix the support structure to the holder body, the holder body has a fixing projection, the support structure being designed to at least partially surround the fixing projection. Preferably, the support structure may also completely surround the fixing projection. Thus, this is a form-fitting connection of the stent body and the support structure. The support structure describes, for example, an arc-shaped portion (when partially encircling) or a ring-shaped portion (when fully encircling). Thus, this is a form-fitting connection of the support structure and the holder body.

During the manufacturing of the stent, the support structure may preferably be flattened in the area of the fixation projections, for example to be flat with the inside of the stent body and not to protrude into the lumen of the stent body.

According to a further embodiment, the fastening projection is arranged in and/or protrudes from a recess of the holder body. For example, the cross section of the recess may be formed in a circular or oval shape and accordingly an aperture is formed in which the fixing projection is arranged and/or from which the fixing projection protrudes. The fastening projection particularly rises from the inner wall of the recess and (first) protrudes into the recess. The support structure is then supported on the inner wall of the recess partially or completely around the fixing projection, whereby a reliable connection is formed between the support structure and the holder body.

The fastening projection can be embodied, for example, as an arc, in particular, only partially protrudes from the recess. The fixing projections preferably protrude from the outside of the stent body so as not to damage the lumen in the inside of the stent body.

According to a further embodiment, for fastening the support structure, the carrier body is connected to the support structure by means of a hooking connection (verhakt), in particular by means of two fastening rings which engage one another, at least one of the fastening rings being open. For example, the support structure may have one or more closed securing loops, while the stent body includes one or more open securing loops. The retaining rings can then be connected to one another like chain links. Alternatively, an open securing ring may be provided on the support structure and a closed securing ring may be provided on the bracket body. The securing ring is preferably an annular disc, but other shapes are possible, such as oval, angular, spoon-shaped (i.e. curved, in particular with the same radius as the holder body). In principle, the shape of the securing ring may be any as long as the securing ring of the holder body can engage into the securing ring of the support structure.

A slit (Schlitz) can be provided in the open fastening ring, which slit is wider than the thickness of the material of the closed fastening ring. Of course, the cut-out may have a maximum width of twice, three times or five times the thickness of the material of the securing ring.

The fixation by the fixation ring is also not a form-fitting connection. Generally, the stent body may be connected to one another by hooks and eyes and a support structure.

According to another embodiment, the hooking connection of the bracket body and the support structure is achieved by means of barbs leading through the opening. As described above, the opening may in particular be a closed securing ring. In this case, the closed securing ring may preferably be attached to the holder body. The barb may be formed of a bioabsorbable material and include a stem having at least two rearwardly oriented hook sections attached to the tip of the stem. The hook sections may collectively define a V-shape. In the manufacture of the stent, the hook sections are guided through the openings in sequence and then prevented from being pulled out. Thus, the fixation of the support structure to the holder body can be achieved by barbs on the support structure.

According to another embodiment, the support structure comprises a plurality of cylindrical sections inside the stent body. The cylindrical section preferably abuts against the inner wall of the holder body. The cylindrical section is formed by cutting the cylinder body along a cylinder axis. The cross-section of the cylindrical section may comprise a sector or a ring section shape. In particular, the ring segments can be combined together to form a hollow cylinder.

According to another embodiment, the cylindrical section forms a cylinder or a hollow cylinder in the compressed state of the stent. When switching to the expanded state, the cylindrical sections then move away from one another and form a particularly built-in track attached to the stent body. The cylindrical section can be fixed to the holder body by means of the fixing means mentioned herein.

Alternatively or additionally to the built-in hollow cylinder, it is also possible that: the support structure may also form an external hollow cylinder or an external tube around the stent body, especially in a compressed state.

In particular, the internal support structure may have different degradation characteristics than the external support structure, e.g., the internal support structure may biodegrade faster than the external support structure. Thus, for example, an internal support structure may degrade completely within minutes or hours, while an external support structure may take days or weeks for complete degradation.

According to another embodiment, the support structure comprises a plurality of recesses or recesses in which the bracket sections of the bracket body are arranged. In this case, the support structure may in particular be external, i.e. arranged on the outside of the holder body. The clearance may also be referred to as a locating clearance. The recess/recess can be adapted for the carrier sections such that a thickening of the support structure is present between the carrier sections. The recess or recess holds the stent sections and stent body in their position. Thus, a precise positioning of the individual stent sections can likewise be achieved by the recesses or recesses when inserted into the hollow organ.

According to a further embodiment, at least two stent sections of the stent body are connected to each other by a connecting element formed of a material of the stent body, wherein a portion of the support structure is attached to the connecting element to strengthen the connecting element. In this embodiment, the carrier sections are designed so as not to be at least partially separated from one another. In order to reinforce the connecting element by means of the bioabsorbable material, the connecting element may be coated, for example, by the bioabsorbable material. Alternatively or additionally, the connecting element may have, for example, a groove or another recess into which the bioabsorbable material of the support structure is introduced. The bioabsorbable material results in an increased stiffness of the connecting element when the stent is inserted into the hollow organ, which in turn results in good positioning properties. After the bioabsorbable material is absorbed, the connecting element is more flexible due to the elimination of additional material, thereby advantageously increasing the flexibility of the stent.

According to a further embodiment, the connecting element has at least partially a thinner and/or tapered material. In particular, the material is thinner and/or tapered compared to the stent section of the stent body. The thinner and/or tapered material is referred to herein only as biostable material of the stent body. Thinner means: for example, the area in the cross-section is smaller and/or the material in the cross-section is less than in a cross-section, e.g. through struts in a stent section. Together with the material of the support structure, the connecting element may have the same thickness as the biostable material in the region of the stent section, or even a thicker thickness than the biostable material in the region of the stent section.

According to a further embodiment, the support structure is pressed against the holder body in at least one fixing recess of the holder body in order to fix the support structure to the holder body by means of a force fit. Preferably, the support structure may be locally compressed with the stent body. The fixation void may be, for example, a hole or through-hole in the stent body into which the bioabsorbable material of the support structure is pressed. The pressing in may be performed, for example, by means of a press head (press), as explained in more detail below. As a result, the bioabsorbable material of the support structure can be pressed against the inner wall of the fixed recess on all sides, wherein the recess also remains in the bioabsorbable material in the center of the fixed recess.

According to another embodiment, the stent body is formed of a storage-shaped, biostable material that occupies the stored shape from the boundary temperature, wherein the biostable material is or comprises, for example, nitinol, as already explained above.

Furthermore, in order to simplify the positioning under the roentgenograph, the support can comprise a plurality of roentgenograph markers, in particular made of tantalum. The rens ray marker may be fixed, for example, on the end of the holder body and/or the support structure viewed in the longitudinal direction. The roentgenographic marking on the support structure can be formed in particular by a material thickening of the bioabsorbable material. Preferably, at least one roentgenographic marker, preferably in the shape of an eyelet, extends away from at least one end of the stent body in the longitudinal direction, wherein the roentgenographic marker has an asymmetric shape. The marker may be a section of the stent body with an increased radiodensity of the roentgens, i.e. particularly well visible in the radiogram of the roentgens. In particular, the marking may be an eyelet, which is filled or covered, for example, by tantalum as described above.

According to another embodiment, the bioabsorbable material comprises zinc. Preferably, the bioabsorbable material is composed of, or comprises, zinc and silver. In particular, the bioabsorbable material comprises 90.0% to 99.95% zinc by mass and 0.05% to 10.0% silver by mass. Such bioabsorbable materials can be eliminated in the blood vessels in the body, for example, within a few weeks.

Alternatively, the bioabsorbable material may also comprise or consist of a polymeric material, for example of polylactic acid (PLA) or poly-L-lactic acid (PLLA). The bioabsorbable material may also include or consist of a magnesium alloy. However, the rennet ray visibility of the stent can be increased by using zinc or zinc alloy as described above, as compared to PLA, PLLA or magnesium alloy. The bioabsorbable material may also be referred to as a biodegradable material.

Combinations of different bioabsorbable materials are also possible. Likewise, the support structure may include one or more different bioabsorbable materials and one or more roentgenographically visible materials.

In particular, the stent body and/or the support structure may also be doped with or coated with an active substance. Such actives may act as antiproliferatives to avoid excessive stent and tissue growth. For example, an antiproliferative agent of the Limus group (Limus-group), a Statine (Statine), a P2Y12 antagonist, or a thrombin antagonist may be used as the active substance.

Another subject of the invention is a stent system having a stent of the type described herein and a catheter in which the stent is accommodated or can be accommodated in a compressed state. The stent is preferably surrounded by a sheath (Hulle) in the catheter. The force required for introducing the stent into the catheter can be reduced, in particular by the rails of the support structure, when introducing the stent into the catheter, i.e. when preparing the stent system. Likewise, the force required for removal from the catheter or sheath can also be reduced, which enables a simpler operation of the stent system. Preferably, the catheter may have a recess at the inner wall, in which recess the rail of the stent, or in general the support structure, is arranged to enable positioning of the stent in the catheter in a simple manner.

The catheter may be part of a so-called introduction instrument, wherein the introduction instrument has in particular an operating mechanism for moving and removing the stent in the hollow organ.

In particular, the catheter may be designed to: upon removal, the stent sections are pulled closer together to simplify removal, and in particular the force required for removal is reduced. Alternatively or additionally, it is possible that the catheter is designed to: when the stent is removed, the stent and in particular the stent body is twisted such that the cells of the stent engage each other like a gear, i.e. the tips of the cells each protrude into the bulge between the two cells ("peak to valley"). In this way, a more continuous surface of the stent can be formed by which alternating rotation of the catheter to the right and left by a few degrees (which is necessary if the tips of the cells of adjacent stent sections are precisely aligned with each other) can be avoided.

Alternatively or additionally, the catheter may also be designed to: the distance between the carrier sections is adjustable during removal, for example in three steps (tight, normal, wide). Such a change in spacing may be achieved by the elasticity of the support structure.

The tensioning and/or twisting of the stent sections can take place, for example, by holding the stent, in particular on the ends of the stent, by means of two separate holding means of the catheter, wherein the two holding means are moved and/or twisted relative to one another.

Another object of the invention is a method for manufacturing a stent having an at least substantially tubular body which extends in a longitudinal direction and which can be converted from a compressed state with a first cross-sectional diameter into an expanded state with an enlarged second cross-sectional diameter, wherein the stent comprises a stent body made of a biostable material, wherein the stent body comprises a plurality of, in particular, mutually separated, preferably annular stent sections, and the stent has a support structure which connects the annular stent sections to one another, wherein the support structure is formed of or comprises a bioabsorbable material, wherein in the method a force is applied to the support structure which has been applied against the stent body to cause deformation of the support structure. For example, the deformation may be flattening of an annular portion of the support structure to press out a portion of the support structure protruding into the interior space from the interior space.

According to one embodiment of the method, the support structure is pressed against the holder body upon application of a force, in order to fix the support structure to the holder body by means of a force fit. The compression is preferably carried out in the fixing recess.

In general, the support structure may be compacted with the stent body at one or more locations, wherein the support structure is covered with material of the stent body and then compacted, for example, in the compacted region.

According to another embodiment of the method, the inner tube is introduced into the stent body as a support (Gegenlager) during the compaction. Compaction may be performed, for example, by a ram having a conical shape. During compression, the inner tube may be introduced into the interior of the stent body as a mating support so that the stent body does not collapse due to the pressure of the ram. The inner tube may have a recess through which the ram can be pushed into the interior of the inner tube during compression. By means of the ram, the support structure can be pressed annularly and/or on all sides against the wall of the fixed recess, wherein in particular the region of material without the support structure is formed centrally in the recess. The area without material forms the location of the ram when it is compressed after removal.

By compacting the support structure and the stent body, a permanent connection can be established between the biostable material and the bioabsorbable material.

The statements made for the stent according to the invention apply correspondingly to the stent system according to the invention and to the method according to the invention. This applies in particular in terms of advantages and embodiments. It is to be understood that all embodiments presented herein can be combined with one another, as long as the contrary is not explicitly stated.

Drawings

The invention is described below purely by way of example with reference to the accompanying drawings. The drawings show:

fig. 1 schematically shows a stent having a stent body and a support structure according to a first embodiment;

fig. 2 schematically shows a unit of a rack and a rail of a support structure according to a second embodiment;

fig. 3 schematically shows a unit of a rack and a rail of a support structure according to a third embodiment;

fig. 4 schematically shows the connection of a support structure according to a fourth embodiment to a stent body.

Fig. 5 schematically shows the fixation of a support structure according to a fifth embodiment to a unit of a stand body;

fig. 6 schematically shows the connection of a support structure with a stent body according to a sixth embodiment;

fig. 7 shows a stent body and a support structure designed as a hollow cylinder inside the stent body divided into cylinder sections (seventh embodiment);

fig. 8 schematically shows a connecting element between stent sections reinforced by bioabsorbable material (eighth embodiment); and

fig. 9 shows a support structure according to a ninth embodiment, wherein the support structure comprises a recess in which the bracket section is arranged.

List of reference numerals

10. Support frame

12. Bracket main body

14. Supporting structure

16. Rail track

18. Unit cell

20. Boundary element

22. Support section

24. Connection section

26. Spring element

28. Tapered portion

30. Serpentine structure

32. Blank part

34. Fixing protrusion

36. Annular part

38. Arc-shaped part

40. Fixing ring

42. Connecting element

44. Cylindrical section

46. Housing part

48. Positioning hollow part

50. Thickening part

Detailed Description

Fig. 1 shows the stent 10 of the first embodiment in an expanded state. The support 10 has a tubular form and extends in the longitudinal direction L. The stent comprises a tubular stent body 12, wherein the stent body 12 is connected to a support structure 14. In fig. 1, the support structure 14 is shown in the form of a plurality of rails 16.

The stent body 12 is formed of a biostable material such as nitinol. The support structure 14 is composed of a bioabsorbable material (e.g., zinc alloy).

For other embodiments, substantially only the differences from the embodiment of fig. 1 are explained.

Fig. 2 shows a second embodiment of the stent 10. Fig. 2 shows a portion of the deployment of the stent 10. The holder body 12 is formed of a unit 18. These cells 18 each have a diamond shape and are formed by plate-like (stegartig) border elements 20.

The holders 10 can also each have an additional unit 18, which is not shown in the figures.

The units 18 shown at the top of fig. 2 are respectively connected with the units 18 shown at the bottom of fig. 2 to create a tubular shape of the stent body 12. The units 18 of the support 10 each form an annular support section 22 which is separated from one another. Each carrier section 22 has rows of cells 18 connected to one another in the circumferential direction. The units 18 of the carrier sections 22 are each connected to the circumferentially adjacent units 18 via two connecting sections 24.

The rail 16 is coupled to the holder body 12 in the region of the connecting section 24. The track 16 is designed to be elongated and straight and extends the entire length of the stent body 12. The individual carrier sections 22 are themselves connected to one another only via the rails 16 of the support structure 14.

Fig. 3 shows a third embodiment of the stent 10. The third embodiment differs from the embodiment according to fig. 2 in that: the rail 16 has a spring element 26 between the two carrier sections 22. The spring element 26 includes a taper 28, the taper 28 being part of a serpentine structure 30. The spring element 26 allows a certain movability of the carrier sections 22 relative to each other.

Fig. 4 shows a fourth embodiment, in which the possibility for connecting the support structure 14 with the carrier body 12 is shown. Fig. 4 shows a recess 32 introduced into the connecting section 24, wherein the fastening projection 34 protrudes into the recess 32. The annular portion 36 or the arcuate portion 38 of the support structure 14 may be disposed about the securing protrusion 34 to secure the support structure 14 to the bracket body 12.

The fifth embodiment shown in fig. 5 likewise comprises a fixing projection 34, around which fixing projection 34 an annular portion 36 of the support structure 14 is arranged. Unlike the embodiment of fig. 4, the fifth embodiment includes oval-shaped cells 18. Furthermore, the fifth embodiment shows a rail 16, the rail 16 being fastened only to every second carrier section 22 (seen in the longitudinal direction L). In addition, the rail 16 is designed to have a length shorter than that of the holder main body 12.

Fig. 6 shows a sixth embodiment of the stent 10. In a sixth embodiment, the support structure 14 is connected to the bracket body 12 by means of a securing ring 40. The bracket body 12 and the support structure 14 have a securing ring 40. The securing ring 14 of the holder body 12 may be open and have a cutout (not shown) through which the securing ring 40 of the support structure 14 may be engaged in the securing ring 40 of the holder body 12. Accordingly, the securing ring 40 of the support structure 14 may be a closed securing ring 40.

In the embodiment according to fig. 6, the individual carrier sections 22 can also be connected to one another by the material of the carrier body 12, more precisely by the connecting elements 42. The connecting elements 42 extend from the ends of the diamond-shaped cells 18 of the stent section 22 to the ends of the cells 18 of the immediately adjacent stent section 22.

Fig. 7 shows a seventh embodiment of the stent 10 in an expanded state. Fig. 7 shows a view in the direction of the longitudinal axis L. Within the stent body 12, the support structure 14 includes a plurality of cylindrical sections 44, the cylindrical sections 44 forming a hollow cylinder in a compressed state. The cylindrical section 44 forms a built-in track 16 within the holder body 12.

Fig. 8 shows an eighth embodiment of the support 10, in which the support sections 22 are connected by means of connecting elements 42. A portion of the deployment of the stent 10 is shown in the upper region of fig. 8 (top view). The lower part of fig. 8 shows a side view of the connecting element 42. The connecting element 42 is formed of a biostable material of the stent body 12 and is reinforced by a bioabsorbable material of the support structure 14. The material of the support structure 14 for reinforcement is accommodated in the receptacle 46 of the connecting element 42, wherein the receptacle 46 can be formed, for example, by a recess in the connecting element 42.

Fig. 9 shows a ninth embodiment of the support 10, wherein a schematic side view of the support 10 is shown. The support 10 in turn comprises a plurality of support sections 22 connected to the support structure 14, wherein the track 16 of the support structure 14 is shown in fig. 9. The rail 16 comprises a plurality of positioning recesses 48 in which the carrier sections 22 are arranged and thus remain in a predetermined position relative to one another. A thickened portion 50 of the track 16 is disposed between the locating recesses 48.

As mentioned above, the different embodiments may be combined with each other. For example, the positioning recess 48 can also be integrated into the rail 16 of the previous embodiment. Also possible are: different connection methods between the bracket body 12 and the support structure 14 are combined with each other.

Common to all embodiments is that: the support structure 14 results in a higher stability of the stent 10 when inserted into a hollow organ. After insertion, the support structure 14 is only temporarily present and absorbed, wherein the advantages obtained after absorption are: the greater flexibility of the stent 10.

Claims

1. A stent (10) for transluminal implantation in a hollow organ, in particular in a blood vessel, ureter, esophagus, colon, duodenum, airway or bile duct, the stent (10) having an at least substantially tubular body extending in a longitudinal direction (L), and the stent (10) being transitionable from a compressed state with a first cross-sectional diameter to an expanded state with an enlarged second cross-sectional diameter,

wherein the stent (10) comprises a stent body (12) made of a biostable material,

it is characterized in that the method comprises the steps of,

the holder body (12) comprises a plurality of, in particular, mutually separate, preferably annular holder sections (22), and

the stent (10) has a support structure (14), the support structure (14) connecting the stent sections (22) to each other, wherein the support structure (14) is formed of or comprises a bioabsorbable material.

2. The stent (10) according to claim 1,

wherein the support structure (14) is designed to hold the carrier sections (22) in a defined relative position to each other

And/or

Wherein the support structure (14) is at least substantially arranged outside the holder body (12).

3. The stent (10) according to at least one of the preceding claims,

wherein the support structure (14) comprises a plurality of rails (16), the rails (16) extending at least substantially parallel to the longitudinal direction,

wherein preferably the tracks (16) are evenly distributed in the circumferential direction of the tubular body and/or have the same length in the longitudinal direction and/or have different positions in the longitudinal direction.

4. A stent (10) according to at least claim 3,

wherein at least one of the rails (16) comprises at least one spring element (26), the spring element (26) having a higher flexibility than the flexibility of the rail (16) in the region outside the spring element (26), wherein the spring element (26) is preferably arranged between two annular carrier sections (22), more preferably centrally between two annular carrier sections (22).

5. The stent (10) according to at least one of the preceding claims,

wherein the support structure (14) is fixed to the holder body (12) by means of a form fit and/or a force fit.

6. The stent (10) according to at least one of the preceding claims,

wherein for fastening the support structure (14) to the support body (12), the support body (12) has fastening projections (34), the support structure (14) being designed to at least partially surround the fastening projections,

wherein the fastening projections (34) are arranged in particular in recesses (32) of the holder body (12) and/or protrude from the recesses (32).

7. The stent (10) according to at least one of the preceding claims,

wherein for fastening the support structure (14), the holder body (12) is connected to the support structure (14) in a hooking manner, in particular by means of two fastening rings (40) which engage one another, wherein at least one of the fastening rings (40) is open,

wherein in particular, the hooking connection of the bracket body (12) and the support structure (14) is realized by means of barbs leading through the opening.

8. The stent (10) according to at least one of claims 1, 2 and 4 to 11,

wherein the support structure (14) comprises a plurality of cylindrical sections (44) in the interior of the stent body (12),

wherein the cylindrical section (44) forms in particular a cylinder or a hollow cylinder in the compressed state of the holder.

9. The stent (10) according to at least one of the preceding claims,

wherein the support structure (14) comprises a plurality of recesses (48) and/or recesses in which the carrier sections (22) of the carrier body (12) are arranged.

10. The stent (10) according to at least one of the preceding claims,

wherein the internal support structure (14) has different degradation characteristics than the external support structure (14), e.g. the internal support structure (14) is able to biodegrade more rapidly than the external support structure (14).

11. The stent (10) according to at least one of the preceding claims,

wherein at least two bracket sections (22) of the bracket body (12) are connected to each other by a connecting element (42) formed of the material of the bracket body (12), wherein a portion of the support structure (14) is attached to the connecting element (42) to strengthen the connecting element (42).

12. The stent (10) according to at least one of the preceding claims,

wherein the support structure (14) is pressed against the holder body (12) in at least one fixing recess of the holder body (12) in order to fix the support structure (14) to the holder body (12) by means of a force fit.

13. A stent system having a stent (10) according to at least one of the preceding claims, and a catheter, in which the stent (10) is accommodated or can be accommodated in a compressed state,

wherein the conduit preferably has a recess on an inner wall in which the support structure of the stent (10) is disposed.

14. The rack system of claim 21 or 22,

wherein the catheter is designed to adjust or change the distance between the stent sections (22) when removed and/or to twist the stent sections (22) relative to each other when removed.

15. A method for manufacturing a stent having an at least substantially tubular body which extends in a longitudinal direction (L) and which can be converted from a compressed state with a first cross-sectional diameter to an expanded state with an enlarged second cross-sectional diameter,

wherein the holder body (12) comprises a plurality of, in particular, mutually separate, preferably annular holder sections (22), and

the stent (10) has a support structure (14) which connects the annular stent sections (22) to one another, wherein the support structure (14) is formed from or comprises a bioabsorbable material,

wherein in the method a force is applied to the support structure (14) that has been brought into abutment with the stent body (12) to cause deformation of the support structure (14).